Wishbone for an automotive suspension

ABSTRACT

A wishbone for an automotive suspension and comprising two sheet metal halves, for attaching the front wheels of a motor vehicle. The wishbone is provided with two points of articulation on the chassis, one behind the other along the direction of travel and representing a horizontal axis ( 5 ) for the wishbone ( 2 ) to tilt around. The wishbone is also provided with one point ( 8 ) of attachment for the suspension. The object is a simpler and hence more cost-effective wishbone. At least one of the points ( 3  &amp;  4 ) of articulation is accordingly a hollow hexagonal cross-section bolt ( 11 ) comprising two halves ( 18  &amp;  19 ) that engages a bearing housing and is an integral component of the wishbone halves ( 14  &amp;  15 ).

[0001] The present invention concerns a wishbone for an automotive suspension and comprising two sheet-metal halves, for attaching the front wheels of a motor vehicle as recited in the preamble to claim 1.

[0002] Wishbones are employed in suspensions with McPherson struts to attach front wheels to a chassis and to control their motion. Such wishbones are usually articulated to the chassis at two points, one behind the other along the direction of travel, and are provided with a single point of attachment for the actual suspension.

[0003] Wishbones in the form of a single sheet-steel module or of two sheet-steel halves are known. Wishbones of cast metal, aluminum for instance, are also known.

[0004] The points of articulation to the chassis and the point of attachment to the suspension are preferably mounted on the wishbones as separate parts. One point of articulation to the chassis can be in the form of a separate hexagonal cross-section bolt that engages a rubber-and-metal bearing housing. Such known wishbones, however, have drawbacks. They are extremely labor intensive to manufacture and must be very precise in order to comply with the tolerances of the components they are attached to.

[0005] The object of the present invention is a wishbone of the aforesaid genus that is easier and hence cheaper to manufacture.

[0006] This object is attained in accordance with the present invention by the characteristics recited in the body of claim 1. Advantageous further and advanced embodiments are addressed in claims 2 through 13.

[0007] The advantage of the present invention is that one point of articulation can itself be part of the wishbone instead of a separate part that needs to be added to it. This approach is not only cheaper, but the absence of the joint also results in greater strength.

[0008] The embodiment illustrated in FIGS. 2 and 3 is particularly advantageous in that bending forces acting high up on the hexagonal cross-section bearing bolt can be transmitted even when the walls of the halves are not particularly thick. The advantage is lower weight, which in turn not only means greater economy but also reduces the non-resiliently supported masses of the suspension.

[0009] One embodiment of the present invention will now be specified with reference to the accompanying drawing, wherein

[0010]FIG. 1 is a perspective view of a front-wheel attachment,

[0011]FIG. 2 is a three-dimensional view of a wishbone,

[0012]FIG. 3 is a larger-scale of the wishbone's rear point of articulation, and

[0013]FIG. 4 is an exploded view of the wishbone prior to assembly.

[0014]FIG. 1 depicts the systems structure of a front-wheel suspension with McPherson struts. The chassis and engine are not represented.

[0015] The individually suspended wheels 1 must be allowed to move up and down while subject to horizontal control on the unillustrated chassis. This requirement is satisfied by wishbones in conjunction with other devices. Each wishbone 2 is articulated to the chassis at two points 3 and 4, one behind the other along the direction of travel. Points 3 and 4 of articulation allow wishbone 2 to tilt around an axis 5 on the chassis. Wishbone 2 is more or less flat and L-shaped, with two shanks 6 and 7. Shank 6 connects points 3 and 4 of articulation, and shank 7 supports a point 8 of attachment.

[0016]FIG. 2 depicts the wishbone 2 for the left front wheel. Front point 3 of articulation is connected to the chassis by a ball-and socket joint 10 that extends into a pin 9, preferably threaded. Rear point 4 of articulation is in the form of a finger-like hexagonal cross-section bearing bolt 11 of constant width. The suspension itself is attached at point 8 of attachment by another ball-and-socket joint 12 that also extends into a pin 13.

[0017] The body of wishbone 2 with its shanks 6 and 7 comprises two stacked halves 14 and 15 welded together at least along their outer contours and at least section to section. Since halves 14 and 15 are punched pressings, the linkage is at least to some extent hollow and provided with punched-out areas 16 and 17 along the middle to reduce weight.

[0018] Bearing bolt 11 is an integral component of the body of wishbone 2, the former's two halves 18 and 19 having been pressed out of the same sheet as body halves 14 and 15, and accordingly also hollow. To facilitate assembly, facets 20 were pressed out at the end of bearing bolt 11 while halves 14 and 15 were being manufactured.

[0019] A reinforcement 22 is accommodated along the interface 21 between halves 14 and 15 and hence between halves 18 and 19 to increase strength and rigidity. The reinforcement 22 in the illustrated embodiment is also of sheet metal, its contour matching that of bearing bolt 11 and of the adjacent area of wishbone 2. Reinforcement 22 extends approximately 1½ the length of bearing bolt 11 into the shank 6 of wishbone 2. The edges of halves 14 and 15 are recessed approximately the thickness of the reinforcement in order to provide space for it.

[0020] To connect wishbone 2 to the chassis at rear point 4 of articulation, bearing bolt 11 is inserted into an unillustrated rubber-and-metal bearing housing secured to the chassis.

[0021]FIG. 4 is an exploded view of all the components illustrated in FIGS. 2 and 3. The illustration depicts the parts before the halves 14 and 15 are welded together and to reinforcement 22.

[0022] As an alternative to welding halves 14 and 15 and reinforcement 22, they can also be cemented together. These components, that is, need not be of steel but can also be of aluminum or plastic for instance. It is also possible to fill the inside of wishbone 2 with plastic. If the insides of the wishbone and bearing bolt are injected with fiber-reinforced plastic, there will in many applications be no need for a reinforcement.

[0023] In particular applications, halves 14 and 15 can be symmetrical not only in certain areas, halves 18 and 19 for example, but also over their total extent. Such a wishbone can be employed for either the left or the right wheel.

[0024] List of parts

[0025]1. wheel

[0026]2. wishbone

[0027]3. front point of articulation

[0028]4. rear point of articulation

[0029]5. tilting axis

[0030]6. shank

[0031]7. shank

[0032]8. point of attachment

[0033]9. pin

[0034]10. ball-and-socket joint

[0035]11. bearing bolt

[0036]12. ball-and-socket joint

[0037]13. pin

[0038]14. body half

[0039]15. body half

[0040]16. punched-out area

[0041]17. punched-out area

[0042]18. bearing-bolt half

[0043]19. bearing-bolt half

[0044]20. facet

[0045]21. interface

[0046]22. reinforcement 

1. Wishbone for an automotive suspension and comprising two sheet metal halves, for attaching the front wheels of a motor vehicle, with two points of articulation on the chassis, one behind the other along the direction of travel and representing a horizontal axis (5) for the wishbone (2) to tilt around, and with one point (8) of attachment for the suspension, characterized in that at least one of the points (3 & 4) of articulation is a hollow hexagonal cross-section bolt (11) comprising two halves (18 & 19) that engages a bearing housing and is an integral component of the wishbone halves (14 & 15).
 2. Wishbone as in claim 1, characterized by a reinforcement (22) inside the bearing bolt (11).
 3. Wishbone as in claim 2, characterized in that the reinforcement (22) extends into the wishbone (2).
 4. Wishbone as in claim 2 or 3, characterized in that the reinforcement (22) more or less fits inside the bearing bolt (11) and occupies it entirely or to some extent.
 5. Wishbone as in claim 2 or 3, characterized in that the reinforcement (22) is of sheet metal and extends more or less along the interface (21) between the halves of the wishbone.
 6. Wishbone as in claim 5, characterized in that the contour of the reinforcement (22) more or less matches that of the bearing bolt (11) and/or that of the adjacent areas of the wishbone and in that one or both of the halves (18 & 19) of the bearing bolt (11) and/or the halves (14 & 15) of the wishbone are provided with a recess matching the thickness of the reinforcement.
 7. Wishbone as in one or more of claims 2 through 6, characterized in that its halves (14 & 15) are of a material similar to that of the reinforcement (22).
 8. Wishbone as in one or more of claims 2 through 7, characterized in that its halves (14 & 15) and the reinforcement (22) are of a ferrous metal.
 9. Wishbone as in one or more of claims 1 through 8, characterized in that its halves (14 & 15) are welded together and/or to the reinforcement (22).
 10. Wishbone as in one or more of claims 1 through 8, characterized in that its halves (14 & 15) are cemented together and/or to the reinforcement (22).
 11. Wishbone as in one or more of claims 2 through 10, characterized in that the hollow space between its halves (14 & 15) is filled with plastic.
 12. Wishbone as in claim 1, characterized in that the hollow space between its halves (14 & 15) and between the halves (18 & 19) of the bearing bolt is filled with plastic.
 13. Wishbone as in one or more of claims 1 through 12, characterized in that its halves (14 & 15) are symmetrical. 